Multiple sclerosis in Denmark (1950-2023): mean age, sex distribution, incidence and prevalence.

With rising life expectancy and advancements in disease management, we expect the multiple sclerosis population is getting older. However, evidence supporting this hypothesis remains sparse. Our study aimed to determine whether the mean age of the Danish multiple sclerosis population has increased and to analyse the developments in sex distribution, incidence, and prevalence, all of which affect age composition. We conducted a cohort study by linking nationwide data from the Danish Multiple Sclerosis Registry to the Population Statistics Registry, the Danish Cause of Death Registry, and the Historical Migration Registry. We included all living patients with a confirmed multiple sclerosis diagnosis who lived in Denmark on the 1st of January each year from 1950 to 2023. We calculated the mean and median age, age distribution, sex distribution, incidence, and prevalence of the Danish MS population annually from 1950 to 2023. We included 28,145 individuals with multiple sclerosis. The mean age of the Danish multiple sclerosis population increased until the late 1970s to around 52.5 years, where it stabilised until 1990. The mean age experienced a slight decline to 51.2 years in 2005, followed by a subsequent rise to its peak of 54.2 years in 2023. In 1975, females comprised 58.7% of the multiple sclerosis population, increasing to 65.7% by 2000 and 68.5% in 2023. The incidence of multiple sclerosis remained stable at around 3.5 per 100,000 until 1975 and steadily increased by more than 2.5 times in 2000 to 11.4 per 100,000. Despite fluctuations, it remained relatively stable from 2000 until 2022, showing a slight decrease in 2022 compared to the previous two decades. Both overall and sex-specific prevalence exhibited an upward trend, particularly among females. Our study demonstrates that the mean age of the Danish multiple sclerosis population has increased, although not as decisively as expected. The female proportion has grown in tandem with prevalence, while incidence appears to have stabilised in recent decades after years of increase. Denmark's robust registry data and universal healthcare system offer a unique opportunity for reliable epidemiological analysis. Our results establish a benchmark for future demographic studies in the field of multiple sclerosis.

Socioeconomic burden of AQP4-antibody seropositive NMOSD: a nationwide registry-based study.

BACKGROUND: AQP4-antibody seropositive (AQP4-Ab+) neuromyelitis optica spectrum disorder (NMOSD) may cause reduced work capability due to disability. Here, we evaluated the socioeconomic status of patients with AQP4-Ab+NMOSD in off-label therapy era compared with the general population. METHODS: A longitudinal nationwide population-based study including all Danish patients with AQP4-Ab+NMOSD and matched controls from the general population. The cohort was linked to other Danish nationwide population-based databases. The study period was from 1992 to 2021. The main outcomes were loss of income from salary, limited work capability, disability pension and civil status. The longitudinal risks of outcomes were presented in cumulative incidence curves. Fisher's exact test, χ2 test or Wilcoxon test were applied for comparison. RESULTS: We included 65 patients with a median follow-up of 8.6 years. Annual income declined significantly after disease onset (index year) compared with the general population. One year after the index year, the median annual income in 2015-indexed Euro for patients averaged 13 285 (IQR: 139 to 36 336) versus controls 33 035 (IQR: 6870 to 45 978); p=0.04. Five years postindex year, the average income for patients further dropped to 276 (IQR: 0 to 23 691) versus controls 22 141 (IQR: 0 to 42 986); p=0.03. At the end of follow-up, significantly higher proportion of patients were either in 'flexjob' (36.9% patients vs 14% controls, p<0.00) or receiving disability pension (16.9% patients vs 4.3% controls, p<0.00). CONCLUSIONS: The socioeconomic status of patients with AQP4-Ab+NMOSD deteriorates rapidly following disease onset. A substantial proportion of these patients lose their work capacity leading to increased financial burden on both their families and society.

Prognostic factors for disease activity in newly diagnosed teriflunomide-treated patients with multiple sclerosis: a nationwide Danish study.

BACKGROUND: Clinicians frequently rely on relapse counts, T2 MRI lesion load (T2L) and Expanded Disability Status Scale (EDSS) scores to guide treatment decisions for individuals diagnosed with multiple sclerosis (MS). This study evaluates how these factors, along with age and sex, influence prognosis during treatment with teriflunomide (TFL). METHODS: We conducted a nationwide cohort study using data from the Danish Multiple Sclerosis Registry.Eligible participants had relapsing-remitting MS or clinically isolated syndrome and initiated TFL as their first treatment between 2013 and 2019. The effect of age, pretreatment relapses, T2L and EDSS scores on the risk of disease activity on TFL were stratified by sex. RESULTS: In total, 784 individuals were included (57.4% females). A high number of pretreatment relapses (≥2) was associated with an increased risk of disease activity in females only (OR and (95% CI): 1.76 (1.11 to 2.81)). Age group 50+ was associated with a lower risk of disease activity in both sexes (OR females=0.28 (0.14 to 0.56); OR males=0.22 (0.09 to 0.55)), while age 35-49 showed a different impact in males and females (OR females=0.79 (0.50 to 1.23); OR males=0.42 (0.24 to 0.72)). EDSS scores and T2L did not show any consistent associations. CONCLUSION: A high number of pretreatment relapses was only associated with an increased risk of disease activity in females, while age had a differential impact on the risk of disease activity according to sex. Clinicians may consider age, sex and relapses when deciding on TFL treatment.

Stress and Multiple Sclerosis - Systematic review and meta-analysis of the association with disease onset, relapse risk and disability progression.

OBJECTIVE: This systematic review and meta-analysis address the evidence on the association of psychological stressors with onset of multiple sclerosis, inflammatory disease activity (relapses or new disease activity on magnetic resonance imaging, MRI) and disability progression. METHODS: PubMed was searched from 1946 to 15 July 2022. Studies and certain stressors were selected when they assessed stressors independent from stress elicited by the disease process itself. Risk of bias was assessed by the CASP Case Control Study Checklist and the CASP Cohort Study Checklist. Normal-Normal Hierarchical Model (NNHM) for random-effects meta-analysis was used in the Bayesian framework. RESULTS: 30 studies reporting data from 26 cohorts reporting on 24.781 cases could be identified. Ten studies addressed stressors and MS disease onset showing a weak to modest effect of psychological stressors. A meta-analysis of three studies investigating diagnosed stress disorders and MS risk showed a 1.87-fold (CI 1.061 to 3.429) increased MS risk. Stress and MS relapse risk were addressed in 19 heterogeneous studies. Meta-analyses from two independent cohorts investigating the same military threat of a population showed a threefold increased risk for relapses in association with war (relapse rate: 3.0, CI 1.56 to 5.81). In addition, two studies confirmed an association of stressful life events and MRI activity. Three studies of stressors and disease progression were included indicating some effect on disease progression. CONCLUSIONS: Taken together studies indicate a minor to modest impact of psychological stressors on disease onset, inflammatory activity and progression of MS. Possible case-selection bias and lack of confounder analysis were present in many studies.

Risk of cardiovascular disease in patients with multiple sclerosis treated with fingolimod compared to natalizumab: A nationwide cohort study of 2095 patients in Denmark.

BACKGROUND: Fingolimod may be associated with risk of developing cardiovascular disease (CVD). Studies including reference groups and long follow-up are scarce. OBJECTIVES: We hypothesized that patients treated with fingolimod would be at higher risk of developing CVD compared to patients treated with natalizumab. METHODS: A nationwide 12-year cohort study linking individual-level data from the Danish Multiple Sclerosis Registry with health registries on 2095 adult patients with multiple sclerosis (MS) without any health records of CVD at follow-up start. Exposure to fingolimod and natalizumab was defined by the first treatment of at least 3 months. Cohort entry was from 2011 to 2018. We defined CVD as a composite measure, including hypertension, ischemic heart disease, atrial fibrillation, heart failure, and stroke. We used multivariable adjusted Cox regression. RESULTS: There were 28.8 and 17.4 CVD events per 1000 person-years in fingolimod and natalizumab groups, respectively. Compared to natalizumab-treated patients, fingolimod-treated patients had a higher risk of CVD (hazard ratio (HR) = 1.57; 95% confidence interval (CI) = 1.18-2.08). Hypertension comprised 200 of 244 CVD events. CONCLUSION: We found an increased risk of CVD in patients with MS treated with fingolimod. This increased risk was mainly due to hypertension.

Torben Fog - A Danish pioneer in a multi-faceted spectrum of multiple sclerosis research.

Torben Fog was committed to multiple sclerosis (MS) research for more than four decades, starting before the defence of his thesis in 1948 and lasting until his death in 1987. His research was multi-facetted, making him one of the great pioneers in the study of essential parts of the pathology, immunology and treatment of MS. He has contributed with meticulous studies of the MS plaques, documenting the perivenous distribution of plaques in the spinal cord. He constructed a scoring system for the disability in MS and used a computer programme to calculate a total neurological deficit. Together with his co-workers, Fog in 1972 was the first to report the association between MS and the human leukocyte antigen system. Fog can be considered as the father of immunomodulatory therapy in MS, treating MS patients with the first transfer factor, and as early as 1980, he was the first to treat MS with intramuscular natural interferon.

Expert opinion on the use of contraception in people with multiple sclerosis.

BACKGROUND: Current guidance on the selection of appropriate contraception for people with multiple sclerosis (PwMS) is lacking. OBJECTIVE: To address this gap, an expert-led consensus program developed recommendations to support clinicians in discussing family planning and contraception with women and men with multiple sclerosis (MS). METHODS: A multidisciplinary steering committee (SC) of 13 international clinical experts led the program, supported by an extended faculty of 32 experts representing 18 countries. A modified Delphi methodology was used for decision-making and consensus-building. The SC drafted 15 clinical questions focused on patient-centered care, selection of contraception, and timing of stopping/starting contraception and disease-modifying therapies (DMTs). Statements addressing each question were drafted based on evaluation of published evidence and the experts' clinical experience. Consensus was reached if ⩾75% of respondents agreed (scoring 7-9 on a 9-point scale) with each recommendation. RESULTS: Consensus was reached on 24 of 25 proposed recommendations, including how and when to discuss contraception, types and safety of contraceptives, and how to evaluate the most appropriate contraceptive options for specific patient groups, including those with significant disability or being treated with DMTs. CONCLUSION: These expert recommendations provide the first practical, relevant, and comprehensive guidance for clinicians on the selection of contraception in PwMS.

Introducing a core dataset for real-world data in multiple sclerosis registries and cohorts: Recommendations from a global task force.

BACKGROUND: As of September 2022, there was no globally recommended set of core data elements for use in multiple sclerosis (MS) healthcare and research. As a result, data harmonisation across observational data sources and scientific collaboration is limited. OBJECTIVES: To define and agree upon a core dataset for real-world data (RWD) in MS from observational registries and cohorts. METHODS: A three-phase process approach was conducted combining a landscaping exercise with dedicated discussions within a global multi-stakeholder task force consisting of 20 experts in the field of MS and its RWD to define the Core Dataset. RESULTS: A core dataset for MS consisting of 44 variables in eight categories was translated into a data dictionary that has been published and disseminated for emerging and existing registries and cohorts to use. Categories include variables on demographics and comorbidities (patient-specific data), disease history, disease status, relapses, magnetic resonance imaging (MRI) and treatment data (disease-specific data). CONCLUSION: The MS Data Alliance Core Dataset guides emerging registries in their dataset definitions and speeds up and supports harmonisation across registries and initiatives. The straight-forward, time-efficient process using a dedicated global multi-stakeholder task force has proven to be effective to define a concise core dataset.

Sleep disorders and sleep disturbances in persons with multiple sclerosis: A population-based matched case-control study in Denmark.

Introduction Adverse sleep is common in multiple sclerosis (MS). Population-based studies including adequate control groups are lacking. We hypothesized that the prevalence of sleep disorders and other sleep disturbances would be higher in persons with MS than in controls. Methods We conducted a population-based study linking individual-level data from the Danish MS Registry (n=21,943 persons with MS) and the Danish Population Registry (n=109,715 matched controls) with information on sleep disorders from the Danish National Patient Registry and other sleep disturbances assessed by dispensed prescription drugs from the Danish National Prescription Registry. Results Prevalence of diagnosed sleep disorders in terms of central hypersomnia (0.15% vs. 0.06%), sleep disturbances (1.05% vs. 0.70%), and sleep movements (0.22% vs. 0.13%) and other sleep disturbances identified by dispensed central acting (10.73% vs. 1.10%) and hypnotic use (30.65% vs. 20.13%) medication was statistically significantly higher among persons with MS when compared to controls. We found no statistically significant difference in the prevalence of sleep apnea and parasomnia between groups. Stratified by sex and age at MS diagnosis, results for differences between persons with MS and controls were similar. Conclusion In this registry-based study, we found that the prevalence of several diagnosed sleep disorders was higher persons with MS than in controls, that is those reflecting insomnia and daytime symptoms including hypersomnia. Other sleep disturbances identified by dispensed prescription medication was markedly higher in persons with MS than controls.

Long-Term Safety of Teriflunomide in Multiple Sclerosis Patients: Results of Prospective Comparative Studies in Three European Countries.

BACKGROUND AND OBJECTIVES: Teriflunomide is a disease-modifying therapy (DMT) for multiple sclerosis (MS). This post authorisation safety study assessed risks of adverse events of special interest (AESI) associated with teriflunomide use. METHODS: Secondary use of individual data from the Danish MS Registry (DMSR), the French National Health Data System (SNDS), the Belgian national database of health care claims (AIM-IMA) and the Belgian Treatments in MS Registry (Beltrims). We included patients treated with a DMT at the date of teriflunomide reimbursement or initiating another DMT. Adjusted hazard rates (aHR) and 95% confidence intervals were derived from Cox models with time-dependent exposure comparing teriflunomide treatment with another DMT. RESULTS: Of 81 620 patients (72% women) included in the cohort, 22 324 (27%) were treated with teriflunomide. After a median follow-up of 4 years, teriflunomide use compared to other DMT was not associated with a risk of all-cause mortality, severe infection, pneumoniae, herpes zoster reactivation, pancreatitis, cardiovascular condition and cancers. For opportunistic infections, aHR for teriflunomide versus other DMT was 2.4 (1.2-4.8) in SNDS, which was not bound to a particular opportunistic agent. The aHR was 2.0 (1.1-3.7) for renal failures in the SNDS, but no association was found in other data sources. A total of 187 SNDS patients had a history of renal failure prior to cohort entry. None of these patients (0%) had a renal failure recurrence when treated with teriflunomide for 19 (13%) recurrences reported for patients on another DMT. DISCUSSION: We found no evidence that teriflunomide use would be associated with an increased risk of AESI. Trial Registration EUPAS register: EU PAS 19610.

Risk of T2 lesions when discontinuing fingolimod: a nationwide predictive and comparative study.

Fingolimod is a frequently used disease-modifying therapy in relapsing-remitting multiple sclerosis. However, case reports and small observational studies indicate a highly increased risk of disease reactivation after discontinuation. We aimed to investigate the risk of radiological disease reactivation in patients discontinuing fingolimod. We performed a nationwide cohort study in Denmark, including patients who discontinued fingolimod between January 2014 and January 2023. Eligibility was a diagnosis with relapsing-remitting multiple sclerosis and two MRIs performed respectively within 1 year before and after discontinuing fingolimod. The included patients were compared with those discontinuing dimethyl fumarate with the same eligibility criteria in an unadjusted and matched propensity score analysis. Matching was done on age, sex, Expanded Disability Status Scale, MRI data, cause for treatment discontinuation, treatment duration and relapse rate. The main outcome was the presence of new T2 lesions on the first MRI after treatment discontinuation. To identify high-risk patients among those discontinuing fingolimod, we made a predictive model assessing risk factors for obtaining new T2 lesions. Of 1324 patients discontinuing fingolimod in the study period, 752 were eligible for inclusion [mean age (standard deviation), years, 41 (10); 552 females (73%); median Expanded Disability Status Scale (Q1-Q3), 2.5 (2.0-3.5); mean disease duration (standard deviation), years, 12 (8)]. Of 2044 patients discontinuing dimethyl fumarate in the study period, 957 were eligible for inclusion, presenting similar baseline characteristics. Among patients discontinuing fingolimod, 127 (17%) had 1-2 new T2 lesions, and 124 (17%) had ≥3 new T2 lesions compared with 114 (12%) and 45 (5%), respectively, for those discontinuing dimethyl fumarate, corresponding to odds ratios (95% confidence interval) of 1.8 (1.3-2.3) and 4.4 (3.1-6.3). The predictive model, including 509 of the 752 patients discontinuing fingolimod, showed a highly increased risk of new T2 lesions among those with disease activity during fingolimod treatment and among females under 40 years. This nationwide study suggests that discontinuing fingolimod in some cases carries a risk of developing new T2 lesions, emphasizing the importance of clinical awareness. If feasible, clinicians should prioritize the prompt initiation of new disease-modifying therapies, particularly among young females.

Risk of Major Types of Dementias Following Hospital-Diagnosed Infections and Autoimmune Diseases.

Background: Population-based studies have shown an increased risk of dementia after infections, but weaker links were reported for autoimmune diseases. Evidence is scarce for whether the links may be modified by the dementia or exposure subtype. Objective: We aimed to investigate the association between infections and/or autoimmune diseases and rates of major types of dementias in the short- and long terms. Methods: Nationwide nested case-control study of dementia cases (65+ years) diagnosed in Denmark 2016-2020 and dementia-free controls. Exposures were hospital-diagnosed infections and autoimmune diseases in the preceding 35 years. Two groups of dementia cases were those diagnosed in memory clinics (MC) and those diagnosed outside memory clinics (non-memory clinic cases, NMC). Results: In total, 26,738 individuals were MC and 12,534 were NMC cases. Following any infection, the incidence rate ratio (IRR) for MC cases was 1.23 (95% CI 1.20-1.27) and 1.70 for NMC cases (1.62-1.76). Long-term increased rates were seen for vascular dementia and NMC cases. IRRs for autoimmune diseases were overall statistically insignificant. Conclusions: Cases with vascular dementia and not Alzheimer's disease, and a subgroup of cases identified with poorer health have increased long-term risk following infections. Autoimmune diseases were not associated with any type of dementia. Notably increased risks (attributed to the short term) and for NMC cases may indicate that immunosenescence rather than de novo infection explains the links. Future focus on such groups and on the role of vascular pathology will explain the infection-dementia links, especially in the long term.

Reevaluating the role of interferon-beta in psoriasis pathogenesis: A registry-based self-controlled study.

Interferon-beta has been suggested as a trigger of psoriasis, yet a systematic investigation is lacking. This study aimed to assess the risk of developing psoriasis following interferon-beta treatment, utilizing a pharmaco-epidemiological approach to investigate the role of interferon-beta in psoriasis pathogenesis. We included all treatment-naïve patients with multiple sclerosis (MS) in Denmark who initiated interferon-beta treatment for MS from January 1996 to June 2023. These patients were compared to a control cohort of patients with MS treated with other disease-modifying drugs. We compared the incidence rates of psoriasis before and during the treatment. Data for this study were extracted from the Danish MS Registry and integrated with information from other national Danish health registries. Among 7174 patients treated with interferon-beta, the incidence rate of psoriasis post-treatment initiation was slightly higher (2.01 per 1000 person-years) compared to the rate prior to treatment (1.67 per 1000 person-years). This increase did not achieve statistical significance (P = 0.53), with an incidence rate ratio (IRR) of 1.20 (95% confidence interval [CI] 0.68-2.13). The control cohort showed an increase in psoriasis incidence post-treatment initiation (3.12 per 1000 person-years) compared to prior (1.11 per 1000 person-years), with an IRR of 2.80 (95% CI 1.36-4.77, P = 0.0038). This registry-based self-controlled study does not support the theory that interferon-beta acts as a trigger for psoriasis development.

Mortality of the Danish Nationwide AQP4 Antibody-Seropositive Neuromyelitis Optica Spectrum Disorder Patient Cohort.

BACKGROUND AND OBJECTIVES: We aimed to evaluate the mortality of patients with AQP4 antibody-seropositive (AQP4-Ab+) neuromyelitis optica spectrum disorder (NMOSD) in Denmark compared with that in the general population. METHODS: We identified patients with AQP4-Ab+ NMOSD fulfilling the 2015 International Panel for Neuromyelitis Optica Diagnosis (IPND) criteria from multiple sources (laboratories and the Danish Multiple Sclerosis Registry). We obtained detailed information about patients from hospital records and about the general population matched on age, sex, and calendar year from Statistics Denmark. We calculated standardized mortality ratio (SMR), excess number of deaths per 1,000 person-years (EDR), and life expectancies compared with those of the matched general population. We examined predictive factors of mortality and the cause of death. RESULTS: Of 66 patients with AQP4-Ab+ NMOSD between 2008 and 2020, 15 died. Overall, the SMR was 2.54 (95% CI 1.47-4.09), and the EDR was 16.8 (95% CI 4.6-34.3). The median life expectancy for patients with AQP4-Ab+ NMOSD was 64.08 years (95% CI 53.02-83.9), compared with 83.07 years for the general population. Risk of death over time was increased in the patient population with a hazard ratio (HR) of 2.22 (1.34-3.68; p = 0.002). The cause of death was directly related to NMOSD in 93% of the cases. The age at disease onset was an independent predictor of death (HR 1.042; 95% CI 1.006-1.079; p = 0.02). DISCUSSION: AQP4-Ab+ NMOSD is associated with increased mortality and shorter life expectancy compared with that in the general population, underlining the need for highly effective treatment approaches.

Big Multiple Sclerosis Data network: an international registry research network.

BACKGROUND: The Big Multiple Sclerosis Data (BMSD) network ( https://bigmsdata.org ) was initiated in 2014 and includes the national multiple sclerosis (MS) registries of the Czech Republic, Denmark, France, Italy, and Sweden as well as the international MSBase registry. BMSD has addressed the ethical, legal, technical, and governance-related challenges for data sharing and so far, published three scientific papers on pooled datasets as proof of concept for its collaborative design. DATA COLLECTION: Although BMSD registries operate independently on different platforms, similarities in variables, definitions and data structure allow joint analysis of data. Certain coordinated modifications in how the registries collect adverse event data have been implemented after BMSD consensus decisions, showing the ability to develop together. DATA MANAGEMENT: Scientific projects can be proposed by external sponsors via the coordinating centre and each registry decides independently on participation, respecting its governance structure. Research datasets are established in a project-to-project fashion and a project-specific data model is developed, based on a unifying core data model. To overcome challenges in data sharing, BMSD has developed procedures for federated data analysis. FUTURE PERSPECTIVES: Presently, BMSD is seeking a qualification opinion from the European Medicines Agency (EMA) to conduct post-authorization safety studies (PASS) and aims to pursue a qualification opinion also for post-authorization effectiveness studies (PAES). BMSD aspires to promote the advancement of real-world evidence research in the MS field.

Predictors of treatment switching in the Big Multiple Sclerosis Data Network.

Background: Treatment switching is a common challenge and opportunity in real-world clinical practice. Increasing diversity in disease-modifying treatments (DMTs) has generated interest in the identification of reliable and robust predictors of treatment switching across different countries, DMTs, and time periods. Objective: The objective of this retrospective, observational study was to identify independent predictors of treatment switching in a population of relapsing-remitting MS (RRMS) patients in the Big Multiple Sclerosis Data Network of national clinical registries, including the Italian MS registry, the OFSEP of France, the Danish MS registry, the Swedish national MS registry, and the international MSBase Registry. Methods: In this cohort study, we merged information on 269,822 treatment episodes in 110,326 patients from 1997 to 2018 from five clinical registries. Patients were included in the final pooled analysis set if they had initiated at least one DMT during the relapsing-remitting MS (RRMS) stage. Patients not diagnosed with RRMS or RRMS patients not initiating DMT therapy during the RRMS phase were excluded from the analysis. The primary study outcome was treatment switching. A multilevel mixed-effects shared frailty time-to-event model was used to identify independent predictors of treatment switching. The contributing MS registry was included in the pooled analysis as a random effect. Results: Every one-point increase in the Expanded Disability Status Scale (EDSS) score at treatment start was associated with 1.08 times the rate of subsequent switching, adjusting for age, sex, and calendar year (adjusted hazard ratio [aHR] 1.08; 95% CI 1.07-1.08). Women were associated with 1.11 times the rate of switching relative to men (95% CI 1.08-1.14), whilst older age was also associated with an increased rate of treatment switching. DMTs started between 2007 and 2012 were associated with 2.48 times the rate of switching relative to DMTs that began between 1996 and 2006 (aHR 2.48; 95% CI 2.48-2.56). DMTs started from 2013 onwards were more likely to switch relative to the earlier treatment epoch (aHR 8.09; 95% CI 7.79-8.41; reference = 1996-2006). Conclusion: Switching between DMTs is associated with female sex, age, and disability at baseline and has increased in frequency considerably in recent years as more treatment options have become available. Consideration of a patient's individual risk and tolerance profile needs to be taken into account when selecting the most appropriate switch therapy from an expanding array of treatment choices.